net/mlx5: Store IPsec ESN update work in XFRM state

mlx5 IPsec code updated ESN through workqueue with allocation calls
in the data path, which can be saved easily if the work is created
during XFRM state initialization routine.

The locking used later in the work didn't protect from anything because
change of HW context is possible during XFRM state add or delete only,
which can cancel work and make sure that it is not running.

Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>